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Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Mar 31, 2015

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Page 1: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Artificial Intelligence

Page 2: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

What is Artificial Intelligence (AI)?

A good question First answer the more

fundamental/basic question:

What is Intelligence?

Page 3: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

What is Intelligence?

If you asked 10 people, you'd probably get 10 answers The ability to learn from experience The power of thought The ability to reason The power of insight Intuition Synonymous with Knowledge

Page 4: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

But What is AI?

Text defn: “the part of computer science that attempts to make computers act like human beings”

• Marvin the Paranoid Android?

Another by Dr. Astro Teller: “A.I. is the science of how to get

machines to do the things they do in the movies.”

So what do they do in the movies?

Page 5: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

YAD of AI

YAD = Yet Another Definition

“Artificial Intelligence is the study of ideas which enable computers to do the things which make people seem intelligent”

And YAD (Patrick Henry Winston): “Artificial intelligence is the study of the

computations that make it possible to perceive, reason, and act.”

Page 6: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

AI: 1956

Solving word problems in algebra

Proving logical theoremsSpeaking English

Page 7: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

1956, Simon: “machines will be capable within twenty years, of doing any work man can do”

1967, Minsky: “Within a generation… the problem of creating ‘artifical intelligence” will substantially be solved.”

Page 8: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Why didn’t it come true?

Page 9: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Why didn’t it come true? Lack of raw computer power

Intractable combinatorial explosion of algorithms

Representing common sense knowledge and doing coming sense reasoning

Incredible difficulty of perception and motion

Failings of logic

Page 10: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

1974:

DARPA cut AI funding

Page 11: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

1980s

Commercial success of expert systems

Page 12: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

1990s

Data mining

Medical diagnosis

Solving specific sub-problems

Page 13: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

The Two Themes of AI

Hard AI – make computers do what humans do Eventually computers will think

Soft AI – make computers more sophisticated Lets make computers better at solving

some of our day-to-day problems

Page 14: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

What Does AI Do?

Play Games

Natural Language Processing

Planning

Diagnosis and analysis

Pattern recognition (handwriting, voice, etc)

Page 15: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Can A Machine Think?

According to Dijkstra: “... the question of whether Machines

Can Think, ... is about as relevant as the question of whether Submarines Can Swim.”

Dijkstra's doubts aside: What “test” can a computer pass to be determined “intelligent”?

Page 16: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

The Turing Test

Proposed by guess who....

“A machine may be deemed intelligent when it can pass for a human being in a blind test.”

That is, if we cannot tell if a computer is a computer, it passes the Turing test.

Page 17: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Turing Test Example

Page 18: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

But

Is the Turing test adequate?

Any potential problems with it?

Page 19: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Is This Adequate?

Possible problems: The machine doesn't understand

things Its success is largely dependent

upon the examiner

Page 20: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

No Understanding

Ex: The Chinese Room Thought Experiment proposed by John Searle

A thought experiment aimed at showing conscious computers are impossible

Page 21: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Chinese Room Thought Experiment

Take a man who does not speak Chinese and lock him in a room

Give him a rule book which indicates how to answer questions in English

Thus he can translate anything from Chinese to English, but has no understanding of Chinese

Page 22: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Success Dependent Upon Examiner

Ex: Eliza - A program which for many people passed the Turing Test

Simulated a psychotherapist by using simple pattern matching and keyword recognition

Page 23: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Success Dependent Upon Examiner

Ex: Eliza - http://www-ai.ijs.si/eliza/eliza.html

Page 24: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Eliza Example

Eliza: “What is bothering you?”

Patient: “I feel sad all the time.”

Eliza: (recognizes “I feel...”): “Why do you feel sad all the time?”

Patient: “I don’t get along with my parents.”

Eliza: (recognizes “my parents”): “Tell me about your parents.”

Is this system Intelligent?

Page 25: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Why Bother With AI?

Because computers are stupid (but powerful)

Wouldn't it be nice if they:

Just knew what you want

Used more common sense

Were more tolerant of errors

Filled in the monotonous details of tasks because they're obvious

AI helps to achieve these goals

Page 26: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Knowledge Representation

How do we encode knowledge in a computer system?

Many possibilities including: Natural Language Formal Language Pictorial Graphical

Page 27: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Natural Language

“There's like, this, like dog, with a whole bunch of spots”

Complex semantics Humans can understand easily Computers not so much

Page 28: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Formal Language

Precise, Complete, Explicit, and most importantly: machine-processable

“There exists a dog. The dog has spots. The number of spots is greater than 10”

Can use formal logic mechanisms to represent

Page 29: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Pictorial

As the saying goes: “A picture is worth 1K words”

Rich for humans (ex maps)

But difficult for computers to understand Ex problem: Face Recognition

Page 30: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Graph-Based

Use graphs to represent a “knowledge network”

Use mathematical properties to analyse or manipulate them

Plus: easy for computers

Page 31: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Evaluating Knowledge Representation Schemes

All Knowledge Representation Schemes should have: Adequacy (captures what you need) Efficient (captures what you need and no

more) Extendible (ability to add new knowledge) Appropriate (good fit for domain and

application)

Page 32: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Games

Early AI work focused on games (ex Chess, Checkers) Easy to represent in a computer Clearly defined rules Unmistakable goals (and besides, games are fun)

Researchers tried to create programs which could win consistently

Page 33: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Games (cont)

Early successes include Arthur Samuel's program for playing checkers in 1952 which could play at a very strong amateur level

More recent successes: IBM's Deep Blue

Page 34: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Games (cont)

While games don't seem practical, many useful techniques emerged from this research including: Solving By Searching Pattern recognition/matching Machine Learning

Lets look at Solving By Searching

Page 35: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Solving By Searching

“Intelligent Searching” in the text

Involves representing the problem as a graph, and finding a solution in the form of a path through the graph

Nodes in the graph are “states” in the problem

Edges represent valid “moves” from one state to another

Page 36: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Solving By Searching (cont)

A problem formulated this way has: A start state

A successor function which tells us which “moves” are valid from a particular state

A goal test to see if we have a solution (if the current state is one of the solution states)

Page 37: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Example Problem - 8-Queens

From chess: can we place 8 queens on a standard 8x8 chess board such that no queen attacks another

Page 38: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

8-Queens

Formulate problem as a tree, where each “node” represents a particular board configuration, and each “child” of a node is another configuration which can result from applying the successor function to the parent

Start state? Successor Function? Goal Test?

Page 39: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

8-Queens As A Graph

.......

Page 40: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

8-Queens

To solve, we just pick the node which represents the starting configuration, and follow paths through the graph until we find one which has the desired solution

Very simple, so what's the problem?

Page 41: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

8-Queens Graph

For 8 queens on a 8x8 board, the graph has:

64! = 64 * 63 * 62 * .... * 2 = 1.8 X 10^4 different configurations

Even worse for larger boards/# of queens

Way too big to search by “brute force”

Can we do better?

informed search strategies

constraint satisfaction problems

See CSC 421 for more info

Page 42: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Expert Systems

Sometimes called “decision support systems”, “knowledge-based systems”, or “rule-based systems”

Systems used to help decision-makers make decisions in complex environments Ex – financial decisions for banks such as

credit checks

Page 43: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Expert Systems (cont)

Consist of: A knowledge base (a set of facts) An inference engine (a mechanism for

selecting relevant facts and reasoning from them)

Page 44: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Expert Systems

Typically encode facts into propositional forms and use formal logic to infer new knowledge from those facts

What programming language does this sound like?

Two main approaches to inference:

Forward chaining – reason from premises to conclusion

Backward chaining – reason from conclusion to premises

Page 45: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Compelling AI today

Your stock portfolio automatically modifies your market position and executes “smart” trades for you.

Your car does your driving for you. Robots handle your housecleaning, yard

work and cooking. Your groceries are automatically ordered

based on preferences and patterns in purchasing.

Page 46: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Compelling AI Today

Your bills and deposits are automatically managed because computer systems have learned your payment schedule.

3rd Generation “smart” search engines that allow you to get your information with more precision to help manage the ever-growing web.

Page 47: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Compelling AI Today

Competitive intelligence is managed by smart AI agents the peruse the web to look for relevant information (new releases, prices, marketing strategies, etc.)

Page 48: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Compelling AI Today

Drug researchers can utilize the intelligence for intensive bio-computational modeling in relation to the enormous amount of data from the human genome project to help find cures in ways never thought of.

Page 49: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Ethical Considerations – Threat to Society?

The view of “hard AI” is that eventually machines will be more intelligent than their creators

Fodder for many sci-fi movies/TV shows/books

Potentially scary, will AI in the future be like Data or The Terminator?

See Theodore John “Ted” Kaczynski

Page 50: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Ethical Considerations – Job Loss?

Technological advancement can render certain jobs redundant

AI (it is argued) will further this trend

Valid concern, or fear of technology? Luddites

Page 51: Artificial Intelligence. What is Artificial Intelligence (AI)? A good question First answer the more fundamental/basic question: What is Intelligence?

Food For Thought

The main lesson of thirty-five years of AI research is that the hard problems are easy and the easy problems are hard. The mental abilities of a four-year-old that we take for granted - recognizing a face, lifting a pencil, walking across the room, answering a question - in fact solve some of the hardest engineering problems ever conceived... As the new generation of intelligent devices appears, it will be the stock analysts and petrochemical engineers and parole board members who are in danger of being replaced by machines. The gardeners, receptionists, and cooks are secure in their jobs for decades to come.

-- Steven Pinker, The Language Instinct